The present invention relates to electric hair clippers, trimmers, and shavers, and more specifically to such devices having fixed blade assemblies which are stationary in use, but detachable relative to the clipper handle.
Disposable manual razors and electric clippers are conventionally used to cut and clip hair for home use, and for the removal of a patient's hair prior to surgery. The razor has a sanitary advantage of being completely disposable, while providing generally stubble-free skin after use. The razor, however, can cause undesirable nicks which, when occurring during pre-operative shaving, may contribute to post-operative infections. Electric clippers are often preferred, therefore, for surgical use. The electric clippers can quickly clear an operation site of a majority of unwanted hair to improve visibility, and without exposure to infections.
FIG. 1 illustrates a conventionally available electric clipper 10. The clipper includes two main components: a combined handle and drive system 12, and a removable, disposable blade assembly 14. The blade assembly 14 includes a housing 16 enclosing a fixed blade 18 and a moving blade 20 coaxially reciprocating relative to the fixed blade 18. When used in medical applications, the blade assembly 14 is typically packaged in a sealed bag for sterility. Just prior to surgery, a hospital technician opens the bag and attaches the blade assembly 14 to the handle/drive system 12. Upon completion of a shaving operation, the blade assembly 14 is removed and discarded.
The blade assembly housing 16 has a flat and rectangular top portion (not shown), from which extend four side portions 24. The four side portions 24 surround an opening 26 of the handle/drive system 12. The blade assembly 14 is pressed by the technician to slide onto the handle/drive system 12, and notches 28 in two opposing sides of the housing 16 then lockingly engage opposing tabs 30 in the handle/drive system 12 to create a “snap” fit. To fit the blade assembly 14 on the handle/drive system 12, the technician typically must hold the handle/drive system 12 with one hand, while gripping the blade assembly 14 with at least two fingers of the other hand.
One disadvantage of this conventional clipper unit 10 is the difficulty in properly engaging the blade assembly on the handle so that a drive member 32, normally a rotating eccentric cam member or reciprocating drive finger, will properly engage a cam follower (not shown) in the reciprocating blade 20 of the blade assembly 14. Such units require the user to often perform relatively complicated multiple alignment and engagement steps to properly mount the blade assembly 14, which can be a frustrating and time consuming procedure.
Another disadvantage of this conventional surgical clipper 10 is that the side portions 24 are very short relative to the blade assembly 14. When sliding the blade assembly 14 onto the handle/drive system 12, the technician is required to place his or her fingers very near the blades 18, 20 of the assembly 14 to exert appropriate pressure, causing the fingers to often contact the exposed teeth of the blades 18, 20. Even when not in operation, upon such contact, the sharp blade teeth may puncture or rupture a thin surgical glove typically worn by a technician performing surgical procedures, thus ruining the sterile environment created by the glove, and possibly infecting the technician with potentially infectious material which may be transmitted by the patient. This potential for infection becomes even greater if the sharp teeth. break the skin of the technician's fingers. Additionally, where a sterile environment is required, the blade assembly must be discarded and replaced before use when the blades contact the technician's skin, which can lead to increased cost from wasted blade assemblies.
Still another disadvantage of this clipper 10 is the significant size of the opening 26 of the handle/drive system 12 which engages the housing side portions 24 of the blade assembly 14. For this configuration, the handle opening 26 must have the same general area as the housing top portion 22. Where a larger surface area of contact is desired for the top portion 22, the size of the handle 12 must therefore be increased to accommodate the area of the top portion 22. The larger the size of the handle 12 though, the more cumbersome the clipper 10 becomes, and the more difficult it becomes to maneuver the blade assembly 14 to shave recessed or contoured portions of the body.
Another surgical clipper with a detachable blade assembly is presented in U.S. Pat. No. 4,700,476 to Locke et al., and shares the same general features as the above-described conventional clipper. The blade assembly housing of this clipper also slides onto the handle/drive system, but instead locks into place under wings that extend from the tip of the drive system about the oscillating member. The oscillating member of the drive system thus engages the drive member of the blade assembly within the blade assembly housing.
This clipper configuration also has the disadvantage, described above, of requiring two hands for assembly and detachment. The similar low profile of its housing and sliding engagement features, also require the technician to push the blade assembly onto the handle from the direction of the blades, often bringing the technician's fingers in direct contact with, and/or pressure from, the sharp blade teeth which, as noted above, can lead to undesirable consequences.
A third known clipper with a detachable blade assembly is shown in U.S. Pat. No. 5,606,799 to Melton. The blade assembly of this clipper is movable and rotatable about the handle portion while in use, and may be easily attached and removed by the operator or technician with only one hand, while avoiding contact of the sharp blade teeth with the technician's fingers. The present inventors have discovered that for some applications, however, it is more desirable to have the blade assembly fixed relative to the handle while in use.